Jeremy Corbyn has called for legislation which would make it necessary for MPs to approve future British military action.

The Labour leader made the call for a War Powers Act as he hit out at the Government's justification for launching airstrikes on Syria in the wake of a chemical weapons attack.

Britain, along with the US and France, hit chemical weapons facilities in a series of raids on three sites during the early hours of Saturday after civilians were targeted in Douma.

Prime Minister Theresa May has insisted the military action was "right and legal". Foreign Secretary Boris Johnson said the world had "finally" said "enough is enough" as he defended the "proportionate" strikes.

But Mrs May's decision not to seek a vote in Parliament beforehand has provoked criticism.

Speaking to the BBC's Andrew Marr show, Mr Corbyn said there should have been a vote ahead of the strikes.

"I think Parliament should have a say in this and I think the Prime Minister could have quite easily done that," he said.

Corbyn questions legality of Syria airstrikes

"She took a decision sometime last week that we were going to work with Macron and Trump in order to have an impact on the chemical weapons establishment in Syria.

"She could have recalled parliament last week - it is only the Prime Minister who can recall parliament - or she could have delayed until tomorrow when Parliament returns. There is precedent over previous interventions when parliament has had a vote.

"I think what we need in this country is something more robust like a War Powers Act so that governments do get held to account by Parliament for what they do in our name."

May: Strikes are not about regime change

Mr Corbyn also questioned Mrs May's assertion that the airstrikes were justified on humanitarian grounds, saying this was "legally debatable".

The Labour leader said that if Britain wants to "get the moral high ground around the world" it has to abide by international law on military action.

When pressed on his own position, Mr Corbyn said he could "only countenance involvement in Syria if there is UN authority behind it".

He added: "If we could get to a process in the UN where you get to a ceasefire, you get to a political solution, you then may well get to a situation where there could be a UN force established to enforce that ceasefire.

"That surely would save a lot of lives."

Syria strikes: Trump hails 'perfect' mission

The stance sparked criticism from opponents, who pointed out that Russia has consistently vetoed UN efforts on Syria.

Some said the stance would effectively give Russian President Vladimir Putin a "veto" over Britain's foreign policy.

Truly Jeremy Corbyn is now Putin's "useful idiot". As a permanent member of the Security Council, Russia has a veto. So Corbyn is saying he will only back action that Putin supports. https://t.co/pDrYc30QiD

Mr Johnson did not rule out further airstrikes when pressed on what would happen if Syria's Bashar al Assad used chemical weapons again.

He told the BBC: "There is no proposal on the table at the moment for further attacks because so far - thank heavens - the Assad regime has not been so foolish to launch another chemical weapons attack.

"If and when such a thing were to happen then clearly, with allies, we would study what the options were."

On Mr Corbyn's War Powers Act suggestion, David Lidington said there were "no plans" for legislation.